"Risky Geo" is a type of fraud that we detect on our platform. IPs marked with Risky Geo means that their location is a factor in increasing the fraud score of that IP.
In brief, we flag countries that have a high historical propensity for fraudulent activity. We base this on an analysis of the traffic we monitor across all of the users in our database.
It's only one indicator of many that we use to score an IP address. Risky Geo adds a small increase to the fraud score of an IP and we don't automatically block users from certain countries.